delphi 取字符串中的数字

function StrGetNumber(QStr: string): string;

var

  i: Integer;

begin

  Result := '';

  for i := Low(QStr) to High(QStr) do

  begin

    case QStr[i] of

      '0'..'9':

        begin

          Result := Result + QStr[i];

        end;

    end;

  end;

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

text:=StrGetNumber('asdfadsfasdfasdf24234234');

end;